Dynamic dropdown population in portlet

[Al Razor]

Hello,

I need to develop a portlet (for GateIn framework), which lists all the clients of the selected company. First, user has to select a city from a dropdown (combobox). Next, another dropdown should be populated (or updated) with a list of companies from the selected city. When the user presses submit, portlet should display the result.

Portlet gets all this information from a few web services (written in PHP) using SOAP 1.1.

It is pretty easy to do it in Java, but in this case I have to integrate code in Java with JSP and JavaScript. And I have very little experience with JavaScript

Therefore, I have the following questions:
1. What is the best way to integrate Java code (functions that return lists) into this JSP page with JavaScript?
2. Would it be easier/more reasonable to re-write it all in JavaScript?

Thanks!